It is now a widely accepted technique to unitize pallet loads of product by encapsulating them in shrink or stretch film. The initial applications primarily involved shrink film, but, with increased emphasis on energy conservation, the use of the stretch film technique is becoming increasingly important.
The principal methods known for stretch-wrapping pallet loads at present are a high-speed system using two rolls of film, as disclosed in U.S. Pat. No. 3,596,434, and a lower-speed system using one roll of film, as disclosed in U.S. Pat. No. 3,867,806. The two-roll system disclosed in U.S. Pat. No. 3,596,434 is a fully automatic system designed for production rates of 100 to 200 loads per hour, and, while it has the advantage of unitizing the pallet load with only one layer of film, it is relatively expensive and has the functional disadvantage of manipulating the load during the wrapping process. In general, it is suitable for only the larger producers. The single roll rotary system as disclosed in U.S. Pat. No. 3,867,806 is a lower cost system which is suitable for smaller producers but has the disadvantage of requiring a minimum of three layers of film to unitize a load.
The present invention, described below, provides film wrap apparatus which operates at relatively high speed, is relatively inexpensive, and requires only a single layer of film to unitize a load.